2001 Chevy Venture minivan

I am having an ongoing problem for a few years with the cooling fans malfunctioning and vehicle overheating. Seems to be an electrical issue. here's what's happened:

(I'm adding here the summary of this issue first to get right to the point cuz I realize the description below is long)

To make a long story short, the cooling fan keeps malfunctioning after being replaced. In the fuse box is a burned wire to the fan relay which has also been replaced and keeps burning. The passenger side fan will run at first when the vehicle is cool, but it stops running when the van heats up. The driver side fan seems to function properly. The vehicle overheats without the fan fully functioning.

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Detailed version:

Dec 2016: Car was overheating. I found the passenger side fan wasnt working. And the 4 pin connector for the fan wire harness was burned on the same side. I replaced the fan motor myself and everything worked again.

July 2018: This time A/C wasnt blowing cold. Mechanic reported low freon & high pressures but also the same passenger side fan not working, both fan connectors burnt & light blue wire going to fan relay in fuse box also burnt. He replaced the whole fan assembly, fan connectors & blue wire. Everyting worked again for several more months.

March 2019: Again vehicle was overheating and fan wasnt running. This time mechanic reported driver side fan not working. Again he found the same wire to the fuse box burnt. Again the whole fan assembly was replaced. Also the 3 fan relays were replaced. Mechanic stated "if happens again will have to take to electrical shop to further diagnose & get fuse box fixed." And it worked again for a few months then failed again.

June 2019: I assumed that maybe the wire burns when the temp gets too high. So I always ran the fans while driving to keep the coolant temp low as possible. This time though the vehicle had been running constantly for about six hours, fans were turned on the whole time. I noticed the vehicle started overheating again. I stopped the vehicle to let it cool, then made it home.

Some days later I tested the fans. I found that when the vehicle is cool both fans run when turned on manually. With the car heated up I turned on the fans at 210F and found the passenger side fan not running. I turned off the fans and let the car continue to run to see if fans turn on automatically. At 233F fans did come on automatically but still passenger side didnt run. I let the vehicle cool and again turned on the fans manually at 150F, again both fans ran. It is evident that both fans are running when the vehicle is cool but the passenger side stops working at some point as the vehicle heats up.

This causes the vehicle to overheat when it isn"t moving enough to get sufficient airflow. At such time the single fan running is not sufficient to cool the engine. The fan fuses and relays remain intact. Apparently at some point as the vehicle heats there is an electrical short that causes a burned wire and one fan to stop running until the car is cooled down.

Obviously the electrical issue needs to be fixed but I'm not sure if the fan motor needs replacement again since it does run when the vehicle's cool. The vehicle did run properly for some time each time the fan motor (or fan assembly) was replaced.

 

I'm not totally for sure, but I believe one fan pushes air, the other pulls. Burnt connections/wire is a result of too much current, undersized conductor, or loose connection(s).